Inside Structure of Dimple for Golf Ball

ABSTRACT

The present invention provides a dimple structure for golf balls. In the present invention, a plurality of dimples ( 50   a ) each having a predetermined shape is disposed on an outer surface of a golf ball in a predetermined arrangement. The dimple structure of the present invention includes at least one protrusion ( 60   a ) which is integrally provided in the dimple ( 50   a ), thus increasing the contact area between the golf ball and the head of a golf club, and increasing resilient force of the golf ball against the golf club head, thereby increasing the distance that the golf ball is driven. As well, the present invention increases the amount of backspin on the golf ball when an approach shot is executed near the putting green, thus allowing the rolling action of the golf ball on the putting green to be easily controlled.

TECHNICAL FIELD

The present invention relates, in general, to dimple structures for golf balls and, more particularly, to a dimple structure for golf balls in which a protrusion is integrally provided in a dimple of a golf ball, thus increasing the contact area between the golf ball and the head of a golf club when striking the golf ball with the golf club, thereby preventing the golf ball from being deformed due to the impact force applied to the golf ball when striking the golf ball, and increasing the distance that the golf ball is driven by increasing the resilient force of the golf ball to promote rapid initial motion of the golf ball, and in which, because a plurality of protrusions gives the golf ball a more closely circular shape, a rolling action of the golf ball on a putting green becomes stable, thus ensuring more precise and accurate putting.

BACKGROUND ART

Generally, golf balls are classified according to the structure thereof into various kinds of golf balls, for example, a one piece golf ball having a single structure, a two piece golf ball which is provided with a core and a cover to surround the core, and a three piece golf ball of a solid type which has a double core structure, including an inner core and an outer core surrounding the inner core, and which is provided with a cover to surround the double core.

Typically, such various golf balls have plural dimples which have predetermined concave shapes and are configured on an outer surface of a golf ball in a predetermined arrangement.

Dimples are intended to improve the driving distance of a golf ball when struck by a golf club by reducing air resistance on the driving golf ball.

Every existing golf ball includes such dimples on an outer surface thereof. Because driving characteristics of a golf ball depend on the disposition, sizes, shapes and depths of the dimples, studies have been conducted on the dimples. In particular, it has been a goal to reduce air resistance on the driven golf ball by varying the shape, number or arrangement of dimples of the golf ball.

However, in conventional golf balls which are provided with dimples having concave shapes, when a golf ball is struck by a golf club, the golf ball may be deformed at a contact surface between the golf ball and the head of the golf club. As such, if the golf ball is deformed when struck by the golf club, air resistance on the golf ball increases. As a result of this, the driven golf ball curves in an undesirable direction. Furthermore, the time required to drive the golf ball using the reaction force and resilient force occurring when the golf ball is struck increases, thus decreasing the distance that the golf ball is driven.

As an example of prior arts to solve the above-mentioned problems, a golf ball having a plurality of reinforcing members as shown in FIGS. 1 and 2 was proposed.

FIG. 1 is a partially exploded perspective view showing the conventional golf ball having the reinforcing members. FIG. 2 is a sectional view of the conventional golf ball having the reinforcing members. As shown in the drawings, the conventional golf ball includes an inner core 10 having an elastic body, an outer core 20 and a cover 30. The reinforcing members 40 are radially provided between the inner core 10 and the outer core 20. Each reinforcing member 40 is made of metal and has a bar shape. Furthermore, a plurality of circular dimples is formed on an outer surface of the cover 30.

In the above-mentioned conventional golf ball having therein the reinforcing members 40, because the reinforcing members 40 are provided in the golf ball in radial directions from the center of the golf ball to the outside, when the golf ball is struck by a golf club, the impact, transmitted from the golf club head to the outer surface of the cover 30 of the golf ball, is gathered through the reinforcing members 40 at the inner core 10, which is located at the center of the golf ball. At this time, the reinforcing members 40 prevent the golf ball from being undesirably deformed due to the impact transmitted from the golf club, thus increasing the distance that the golf ball is driven.

However, the conventional golf ball having the reinforcing members therein is problematic in that manufacturing costs increase due to the separate reinforcing members. Furthermore, because the reinforcing members are made of metal bars, when impact is transmitted from a golf club to the golf ball, the elastic inner and outer cores and the cover may be damaged by the reinforcing members.

In FIG. 3, a golf ball having a plurality of impact transmission members therein is shown as another example of prior arts unlike the golf ball of FIGS. 1 and 2.

FIG. 3 is a sectional view showing the golf ball having the impact transmission members therein. As shown in FIG. 3, this golf ball includes a spherical inner core 10 which is positioned at the center of the golf ball and has a first core 10 a and a second core 10 b, and an outer core 20 which surrounds an outer surface of the inner core 10. The golf ball further includes the impact transmission members 40 a which are placed in the outer core 20 and supported by the inner core 10 to transmit outside impact to the inner core 10. The golf ball further includes a cover 30 which surrounds the outer core 20 and prevents the impact transmission members 40 a from being exposed to the outside.

In the above-mentioned conventional golf ball having the impact transmission members 40 a, because the impact transmission members 40 a are provided in the golf ball in radial directions from the center of the golf ball to the outside, when the golf ball is struck by a golf club, the impact, transmitted from the golf club head to the outer surface of the cover 30 of the golf ball, is transmitted through the impact transmission members 40 a to the first core 10 a of the inner core 10 which is placed at the center of the golf ball. At this time, the impact transmission members 40 a prevent the golf ball from being deformed due to the impact transmitted from the golf club, thus increasing the distance that the golf ball is driven.

In other words, when impact energy from the golf club head is applied to the golf ball, the impact energy is transmitted to the first core of the inner core via the cover and the impact transmission members. This impact energy acts as the force to drive the golf ball. At this time, reaction force reacting to the impact energy transmitted to the inner core is generated in the golf ball. This reaction force is transmitted to the cover through the impact transmission members, thus preventing the golf ball from being deformed at the impact portion thereof at which the golf ball comes into contact with the golf club head.

However, this golf ball has a problem of increased manufacturing costs due to the separate impact transmission members, as in the above-mentioned golf ball having therein the reinforcing members. Furthermore, the productivity is reduced. In addition, in a process of striking the golf ball with a golf club, the impact transmission members may damage the elastic inner and outer cores and the cover when the impact is transmitted to impact transmission members.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a dimple structure for golf balls in which a protrusion is integrally provided in a dimple of a golf ball having a concave shape, thus increasing the contact area between the golf ball and the head of a golf club when striking the golf ball with the golf club, and increasing the resilient force of the golf ball against the golf club head, thereby increasing the distance that the golf ball is driven.

Another object of the present invention is to provide a dimple structure for golf balls which is able to prevent a golf ball, which comes into contact with the head of a golf club when struck by the golf club, from being undesirably deformed, and increase the resilient force of the golf ball to promote a rapid initial motion of the golf ball.

A further object of the present invention is to provide a dimple structure for golf balls in which, as a plurality of protrusions gives a golf ball a more closely circular shape, a rolling action of the golf ball on a putting green becomes stable, thus ensuring more precise and accurate putting, and which is able to increase the amount of backspin on the golf ball when an approach shot is executed near the putting green, thus allowing the rolling action of the golf ball on the putting green to be easily controlled.

Yet another object of the present invention is to provide a dimple structure for golf balls which prevents the elastic inner and outer cores and a cover of a golf ball from damage.

Still another object of the present invention is to provide a dimple structure for golf balls which is able to enhance productivity and reduce manufacturing costs.

Technical Solution

In order to accomplish the above objects, the present invention provides a dimple structure for golf balls, wherein a plurality of dimples each having a predetermined shape is disposed on an outer surface of a golf ball in a predetermined arrangement, the dimple structure including: at least one protrusion integrally provided in the dimple, thus increasing the contact area between the golf ball and the head of a golf club when striking the golf ball with the golf club, and increasing the resilient force of the golf ball against the golf club head, thereby increasing the distance that the golf ball is driven.

Furthermore, the protrusion constituting the dimple structure for golf balls may have various shapes or may have the same shape as that of the dimple. The protrusion may be provided between an outer circumferential line and an inner circumferential line between which a depth of the dimple is defined, so that the protrusion does not protrude outside the outer circumferential line, thus reducing the air resistance on the driving golf ball, and ensuring the superior rolling performance of the golf ball.

In addition, the protrusion constituting the dimple structure for golf balls may be provided in each dimple of the golf ball or, alternatively, it may be evenly provided in 15% to 85% of the dimples of the golf ball such that the center of gravity of the golf ball exists at the same point in the golf ball regardless of the orientation of the golf ball.

As well, the protrusion constituting the dimple structure for golf balls may have a size of 5% to 60% of the surface area of the dimple, thus reducing the weight of the golf ball.

Advantageous Effects

A dimple structure for golf balls according to present invention, at least one protrusion is integrally provided in a dimple of a golf ball having a concave shape of an engraving pattern, thus increasing the contact area between the golf ball and the head of a golf club when striking the golf ball with the golf club, and increasing the resilient force of the golf ball against the golf club head, thereby increasing the distance that the golf ball is driven.

Furthermore, the dimple structure for golf balls is able to prevent the golf ball, which comes into contact with the head of a golf club when struck by the golf club, from being undesirably deformed, and increase the resilient force of the golf ball to promote rapid initial motion of the golf ball.

Moreover, in the dimple structure for golf balls according to the present invention, as a plurality of protrusions gives the golf ball a more closely circular shape, a rolling action of the golf ball on a putting green becomes stable, thus ensuring more precise and accurate putting. As well, the present invention is able to increase the amount of backspin on the golf ball when an approach shot is executed near the putting green, thus allowing the rolling action of the golf ball on the putting green to be easily controlled.

In addition, the dimple structure for golf balls prevents the elastic inner and outer cores and the cover of the golf ball from damage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view showing a conventional golf ball having a plurality of reinforcing members therein;

FIG. 2 is a sectional view of the conventional golf ball having the reinforcing members;

FIG. 3 is a sectional view showing another conventional golf ball having a plurality of impact transmission members therein;

FIG. 4 is a sectional view of a golf ball provided with a plurality of dimples each having therein a protrusion according to the present invention;

FIG. 5 is a sectional view showing a protrusion provided in a relatively wide dimple of a golf ball, according to the present invention;

FIGS. 6 and 7 are sectional views showing protrusions provided in relatively small dimples of golf balls, according to the present invention;

FIGS. 8 through 12 are sectional views showing various shapes of protrusions forming a dimple structure for golf balls, according to the present invention;

FIG. 13 is a perspective view showing a dimple structure for a golf ball, according to a first embodiment of the present invention;

FIG. 14 is a sectional view of the golf ball of FIG. 13;

FIG. 15 is a sectional view showing a part of the golf ball to illustrate the height of the protrusion according to the first embodiment of the present invention;

FIG. 16 is a sectional view showing a part of the golf ball to illustrate the size of the protrusion according to the first embodiment of the present invention;

FIG. 17 is a perspective view showing a dimple structure for a golf ball, according to a second embodiment of the present invention;

FIG. 18 is a sectional view of the golf ball of FIG. 17;

FIG. 19 is a perspective view showing a dimple structure for a golf ball, according to a third embodiment of the present invention;

FIG. 20 is a sectional view of the golf ball of FIG. 19;

FIG. 21 is a perspective view showing a dimple structure for a golf ball, according to a fourth embodiment of the present invention;

FIG. 22 is a sectional view of the golf ball of FIG. 21;

FIG. 23 is a perspective view showing a dimple structure for a golf ball, according to a fifth embodiment of the present invention;

FIG. 24 is a perspective view showing a dimple structure for a golf ball, according to a sixth embodiment of the present invention; and

FIG. 25 is a sectional view showing a golf ball provided with a plurality of dimples each having two protrusions therein, according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

FIG. 13 is a perspective view showing a dimple structure for a golf ball, according to a first embodiment of the present invention. FIG. 14 is a sectional view of the golf ball of FIG. 13. FIG. 15 is a sectional view showing a part of the golf ball to illustrate the height of the protrusion according to the first embodiment of the present invention. FIG. 16 is a sectional view showing a part of the golf ball to illustrate the size of the protrusion according to the first embodiment of the present invention.

As shown in the drawings, a plurality of dimples 50 a each having a circular concave shape is disposed on the golf ball 1 in a predetermined arrangement. The dimple structure for golf balls according to the first embodiment of the present invention includes at least one protrusion 60 a which has the same circular shape as that of the dimple 50 a and is integrally provided in the dimple 50 a.

The protrusion 60 a is not limited to the circular shape, but it may be shaped differently from the shape of the dimple 50 a. That is, the protrusion 60 a may be formed in various shapes, such as a rectangular, square, cylindrical or pyramid shape. Alternatively, several protrusions 60 a having different shapes may be simultaneously used.

Preferably, a circular protrusion 60 a is provided in each of the dimples 50 a. As such, a golf ball in which a circular protrusion 60 a is provided in each dimple 50 a is suitable for golf beginners. That is, because the circular protrusions 60 a are evenly formed throughout the entire surface of the golf ball, although a golf beginner may strike any portion of the golf ball with a golf club, the head of the golf club comes into contact with a portion of the golf ball in which circular protrusions 60 a exist.

In this case, there is a problem of increased weight of the golf ball, but this problem can be solved by changing the material or size of an inner core of the golf ball, or the material or size of a cover, or the depth or area of the dimples in a process of manufacturing the golf ball.

It is preferred that the circular protrusion 60 a be provided in 15% to 85% of the dimples 50 a of the golf ball 1. Here, the circular protrusions 60 a are evenly arranged such that the center of gravity of the golf ball 1 exists at the same point in the golf ball 1 regardless of the orientation of the golf ball 1.

If the number of circular protrusions 60 a is 15% or less of the number of dimples 50 a of the golf ball 1, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club. Then, the resilient force of the golf ball 1 against the golf club head is not increased. On the other hand, if the number of circular protrusions 60 a is 85% or more of the number of dimples 50 a of the golf ball 1, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced.

A golf ball, in which the number of circular protrusions 60 a is 15% to 50% of the number of dimples 50 a, is suitable for expert golfers. A golf ball, in which the number of circular protrusions 60 a is 50% to 85% of the number of dimples 50 a, is suitable for intermediate golfers.

This is because, in the case of a golf ball 1 having a small number of circular protrusions 60 a, it is difficult for golf beginners or intermediate golfers to precisely strike the portion of the golf ball in which the circular protrusions 60 a are formed to increase the resilient force of the golf ball.

Preferably, in consideration of both air resistance when the golf ball 1 is driven and a rolling movement of the golf ball 1 on a putting green, the height of each circular protrusion 60 a is the same as or less than the depth (D) of the dimple 50 a (see, FIG. 15).

In other words, as shown in FIGS. 4 through 7, each circular protrusion 60 a is positioned between an outer circumferential line (a) of the golf ball 1 and an inner circumferential line (b) without protruding outside an outer circumferential line (a) of the golf ball 1.

This is because, if the circular protrusion 60 a protrudes outside the dimple 50 a (outside the outer circumferential line (a) of the golf ball 1), there are several problems, specifically, it becomes difficult to correctly strike the golf ball 1, the distance that the golf ball 1 is driven is reduced due to the increased air resistance, and the golf ball 1 cannot smoothly roll on a putting green.

Furthermore, the circular protrusion 60 a has a size of 5% to 60% of a cross-sectional area (A) of the dimple 50 a (see, FIG. 16). This is because, if the size of the circular protrusion 60 a occupies 5% of or less than the cross-sectional area (A) of the dimple 50 a, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club so that the resilient force of the golf ball 1 against the golf club head is not increased. Furthermore, if the size of the circular protrusion 60 a occupies 60% or more of the cross-sectional area (A) of the dimple 50 a, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced, as in the description of the physical phenomenon according to the height of the protrusion 60 a.

As such, in the present invention, in the center of the dimple 50 a having the circular concave shape, at least one protrusion 60 a having the same circular shape as that of the dimple 50 a is integrally provided. Thus, as the circular protrusions 60 a come into contact with the head of a golf club when striking the golf ball 1 with the golf club, the golf ball 1 is prevented from being deformed. Furthermore, because the contact surface (the impact surface) between the golf ball 1 and the golf club head is increased, the resilient force of the golf ball 1 is increased.

Moreover, the circular protrusions 60 a give the golf ball a more closely circular shape. Therefore, the golf ball can more smoothly roll on the putting green, so that, when putting, a golfer can putt more precisely and accurately. In addition, because the amount of backspin on the golf ball 1 can be increased when executing an approach shot near the putting green, the rotation of the golf ball can be easily controlled. In other words, as it is possible to increase the amount of backspin on the golf ball due to the circular protrusions 60 a which give the golf ball a more closely circular shape, a stop point of the golf ball can be easily controlled by controlling the rotation of the golf ball (controlling the amount of backspin on the golf ball).

FIG. 17 is a perspective view showing a dimple structure for a golf ball, according to a second embodiment of the present invention. FIG. 18 is a sectional view of the golf ball of FIG. 17.

As shown in the drawings, a plurality of dimples 50 b each having an elliptical concave shape is disposed on the golf ball 1 in a predetermined arrangement. The dimple structure for golf balls according to the second embodiment of the present invention includes at least one protrusion 60 b which has the same elliptical shape as that of the dimple 50 b and is integrally provided in the dimple 50 b.

The protrusion 60 b is not limited to the elliptical shape, but it may be shaped differently from the shape of the dimple 50 b. That is, the protrusion 60 b may be formed in various shapes, such as a circular, rectangular, square, cylindrical or pyramid shape. Alternatively, several protrusions 60 b having different shapes may be simultaneously used.

Preferably, the elliptical protrusion 60 b is provided in each of the dimples 50 b.

Further, it is preferred that the elliptical protrusion 60 b be provided in 15% to 85% of the dimples 50 b of the golf ball 1. Here, the elliptical protrusions 60 b are evenly arranged such that the center of gravity of the golf ball 1 exists at the same point in the golf ball 1 regardless of the orientation of the golf ball 1.

If the number of elliptical protrusions 60 b is 15% or less of the number of dimples 50 b of the golf ball 1, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club. Then, the resilient force of the golf ball 1 against the golf club head is not increased. On the other hand, if the number of elliptical protrusions 60 b is 85% or more of the number of dimples 50 b of the golf ball 1, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced.

Furthermore, in consideration of both air resistance when the golf ball 1 is driven and a rolling movement of the golf ball 1 on a putting green, preferably, the height of each elliptical protrusion 60 b is the same as or less than the depth (D) of the dimple 50 b (see, FIG. 15).

In other words, as shown in FIGS. 4 through 7, each elliptical protrusion 60 b is positioned between an outer circumferential line (a) of the golf ball 1 and an inner circumferential line (b) without protruding outside an outer circumferential line (a) of the golf ball 1.

This is because, if the elliptical protrusion 60 b protrudes outside the dimple 50 b (outside of the outer circumferential line (a) of the golf ball 1), there are several problems, specifically, it becomes difficult to correctly strike the golf ball 1, the distance that the golf ball 1 is driven is reduced due to the increased air resistance and, the golf ball 1 cannot smoothly roll on a putting green.

Furthermore, the elliptical protrusion 60 b has a size of 5% to 60% of a cross-sectional area (A) of the dimple 50 b (see, FIG. 16). This is because, if the size of the elliptical protrusion 60 b occupies 5% of or less than the cross-sectional area (A) of the dimple 50 b, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club, so that the resilient force of the golf ball 1 against the golf club head is not increased. Furthermore, if the size of the elliptical protrusion 60 b occupies 60% or more of the cross-sectional area (A) of the dimple 50 b, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced, as in the description of the physical phenomenon according to the height of the protrusion 60 b.

As such, in the present invention, in the center of the dimple 50 b having the elliptical concave shape, at least one protrusion 60 b having the same elliptical shape as that of the dimple 50 b is integrally provided. Thus, as the elliptical protrusions 60 b come into contact with the head of a golf club when striking the golf ball 1 with the golf club, the golf ball 1 is prevented from being deformed and, as well, an increase in resilient force of the golf ball 1 to promote a rapid initial motion is ensured.

FIG. 19 is a perspective view showing a dimple structure for a golf ball, according to a third embodiment of the present invention. FIG. 20 is a sectional view of the golf ball of FIG. 19.

As shown in the drawings, a plurality of dimples 50 c each having an equilateral octagonal concave shape is disposed on the golf ball 1 in a predetermined arrangement. The dimple structure for golf balls according to the third embodiment of the present invention includes at least one protrusion 60 c which has the same equilateral octagonal shape as that of the dimple 50 c and is integrally provided in the dimple 50 c.

The protrusion 60 c is not limited to the equilateral octagonal shape, but it may be shaped differently from the shape of the dimple 50 c. That is, the protrusion 60 c may be formed in various shapes, such as a circular, elliptical, rectangular, square, cylindrical or pyramid shape. Alternatively, several protrusions 60 c having different shapes may be simultaneously used.

Preferably, the equilateral octagonal protrusion 60 c is provided in each of the dimples 50 c.

Further, it is preferred that the equilateral octagonal protrusion 60 c be provided in 15% to 85% of the dimples 50 c of the golf ball 1. Here, the equilateral octagonal protrusions 60 c are evenly arranged such that the center of gravity of the golf ball 1 exists at the same point in the golf ball 1 regardless of the orientation of the golf ball 1.

If the number of equilateral octagonal protrusions 60 c is 15% or less of the number of dimples 50 c of the golf ball 1, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club. Then, the resilient force of the golf ball 1 against the golf club head is not increased. On the other hand, if the number of equilateral octagonal protrusions 60 c is 85% or more of the number of dimples 50 c of the golf ball 1, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced.

Furthermore, in consideration of both air resistance when the golf ball 1 is driven and a rolling movement of the golf ball 1 on a putting green, preferably, the height of each equilateral octagonal protrusion 60 c is the same as or less than the depth (D) of the dimple 50 c (see, FIG. 15).

In other words, as shown in FIGS. 4 through 7, each equilateral octagonal protrusion 60 c is positioned between an outer circumferential line (a) of the golf ball 1 and an inner circumferential line (b) without protruding outside an outer circumferential line (a) of the golf ball 1.

This is because, if the equilateral octagonal protrusion 60 c protrudes outside the dimple 50 c (outside of the outer circumferential line (a) of the golf ball 1), there are several problems, specifically, it becomes difficult to correctly strike the golf ball 1, the distance that the golf ball 1 is driven is reduced due to the increased air resistance and, the golf ball 1 cannot smoothly roll on a putting green.

Furthermore, the equilateral octagonal protrusion 60 c has a size of 5% to 60% of a cross-sectional area (A) of the dimple 50 c (see, FIG. 16). This is because, if the size of the equilateral octagonal protrusion 60 c occupies 5% of or less than the cross-sectional area (A) of the dimple 50 c, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club, so that the resilient force of the golf ball 1 against the golf club head is not increased. Furthermore, if the size of the equilateral octagonal protrusion 60 c occupies 60% or more of the cross-sectional area (A) of the dimple 50 c, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced, as in the description of the physical phenomenon according to the height of the protrusion 60 c.

As such, in the present invention, on the center of the dimple 50 c having the equilateral octagonal concave shape, at least one protrusion 60 c having the same equilateral octagonal shape as that of the dimple 50 c is integrally provided. Thus, as the equilateral octagonal protrusions 60 c come into contact with the head of a golf club when striking the golf ball 1 with the golf club, the golf ball 1 is prevented from being deformed and, as well, an increase in resilient force of the golf ball 1 to promote a rapid initial motion is ensured.

FIG. 21 is a perspective view showing a dimple structure for a golf ball, according to a fourth embodiment of the present invention. FIG. 22 is a sectional view of the golf ball of FIG. 21.

As shown in the drawings, a plurality of dimples 50 d each having a non-equilateral octagonal concave shape is disposed on the golf ball 1 in a predetermined arrangement. The dimple structure for golf balls according to the fourth embodiment of the present invention includes at least one protrusion 60 d which has the same non-equilateral octagonal shape as that of the dimple 50 d and is integrally provided in the dimple 50 d.

The protrusion 60 d is not limited to the non-equilateral octagonal shape, but it may be shaped differently from the shape of the dimple 50 d. That is, the protrusion 60 d may be formed in various shapes, such as a circular, elliptical, rectangular, square, cylindrical or pyramid shape. Alternatively, several protrusions 60 d having different shapes may be simultaneously used.

Preferably, the non-equilateral octagonal protrusion 60 d is provided in each of the dimples 50 d.

Further, it is preferred that the non-equilateral octagonal protrusion 60 d be provided in 15% to 85% of the dimples 50 d of the golf ball 1. Here, the non-equilateral octagonal protrusions 60 d are evenly arranged such that the center of gravity of the golf ball 1 exists at the same point in the golf ball 1 regardless of the orientation of the golf ball 1.

If the number of non-equilateral octagonal protrusions 60 d is 15% or less of the number of dimples 50 d of the golf ball 1, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club. Then, the resilient force of the golf ball 1 against the golf club head is not increased. On the other hand, if the number of non-equilateral octagonal protrusions 60 d is 85% or more of the number of dimples 50 d of the golf ball 1, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced.

Furthermore, in consideration of both air resistance when the golf ball 1 is driven and a rolling movement of the golf ball 1 on a putting green, preferably, the height of each non-equilateral octagonal protrusion 60 d is the same as or less than the depth (D) of the dimple 50 d (see, FIG. 15).

In other words, as shown in FIGS. 4 through 7, each non-equilateral octagonal protrusion 60 d is positioned between an outer circumferential line (a) of the golf ball 1 and an inner circumferential line (b) without protruding outside an outer circumferential line (a) of the golf ball 1.

This is because, if the non-equilateral octagonal protrusion 60 d protrudes outside the dimple 50 d (outside of the outer circumferential line (a) of the golf ball 1), there are several problems, specifically, it becomes difficult to correctly strike the golf ball 1, the distance that the golf ball 1 is driven is reduced due to the increased air resistance and, the golf ball 1 cannot smoothly roll on a putting green.

Furthermore, the non-equilateral octagonal protrusion 60 d has a size of 5% to 60% of a cross-sectional area (A) of the dimple 50 d (see, FIG. 16). This is because, if the size of the non-equilateral octagonal protrusion 60 d occupies 5% of or less than the cross-sectional area (A) of the dimple 50 d, there is little effect of increasing a contact area of an impact surface between the golf ball 1 and the head of a golf club when striking the golf ball 1 with the golf club, so that the resilient force of the golf ball 1 against the golf club head is not increased. Furthermore, if the size of the non-equilateral octagonal protrusion 60 d occupies 60% or more of the cross-sectional area (A) of the dimple 50 d, because the weight of the golf ball 1 is increased and, as well, air resistance is increased, the distance that the golf ball 1 is driven is reduced, as in the description of the physical phenomenon according to the height of the protrusion 60 d.

As such, in the present invention, in the center of the dimple 50 d having the non-equilateral octagonal concave shape, at least one protrusion 60 d having the same non-equilateral octagonal shape as that of the dimple 50 d is integrally provided. Thus, as the non-equilateral octagonal protrusions 60 d come into contact with the head of a golf club when striking the golf ball 1 with the golf club, the golf ball 1 is prevented from being deformed and, as well, an increase in resilient force of the golf ball 1 to promote a rapid initial motion is ensured.

FIG. 23 is a perspective view showing a dimple structure for a golf ball, according to a fifth embodiment of the present invention. A plurality of dimples 50 e each having an equilateral hexagonal concave shape is configured on the golf ball 1 in a predetermined shape. The dimple structure for golf balls according to the fifth embodiment of the present invention includes at least one protrusion 60 e which has the same equilateral hexagonal shape as that of the dimple 50 e and is integrally provided in the dimple 50 e. Here, the protrusion 60 e may have various shapes without being limited to the equilateral hexagonal shape.

FIG. 24 is a perspective view showing a dimple structure for a golf ball, according to a sixth embodiment of the present invention. A plurality of dimples 50 f each having a non-equilateral hexagonal concave shape is configured on the golf ball 1 in a predetermined shape. The dimple structure for golf balls according to the sixth embodiment of the present invention includes at least one protrusion 60 f which has the same non-equilateral hexagonal shape as that of the dimple 50 f and is integrally provided in the dimple 50 f. Here, the protrusion 60 f may have various shapes without being limited to the non-equilateral hexagonal shape.

The protrusion constituting the dimple structure of each of the fifth and sixth embodiments of the present invention has the same structure as that of the above-mentioned first through fourth embodiments.

FIG. 25 is a sectional view showing a golf ball 1 provided with a plurality of dimples each having two protrusions therein, according to the present invention.

In FIG. 25, two protrusions having the same shape are provided in each dimple, but two protrusions having different shapes may be provided in each dimple.

Preferably, the two protrusions are provided in each of the dimples.

Further, it is preferred that a pair of protrusions be provided in 15% to 85% of the dimples of the golf ball. Here, a plurality pairs of protrusions are evenly arranged such that the center of gravity of the golf ball exists at the same point in the golf ball regardless of the orientation of the golf ball.

Furthermore, in consideration of both air resistance when the golf ball is driven and a rolling movement of the golf ball on a putting green, preferably, the height of each protrusion is the same as or less than the depth (D) of the dimple (see, FIG. 15).

Furthermore, the sum of the areas of the protrusions occupies 5% to 60% of the cross-sectional area (A) of the dimple (see, FIG. 16).

The reason, why the total size of protrusions is limited within a predetermined percentage range is the same as the reason for the percentage limitation of the number of protrusions in each embodiment which was described above.

The features of the dimple structure for golf balls according to each embodiment of the present invention will be explained below in brief.

First, the dimple structure for golf balls according to the present invention is characterized by the protrusion capable of being applied to any golf ball having dimples regardless of the kind of golf ball, such as one-piece, two-piece or three-piece golf ball.

Second, the dimple structure for golf balls according to the present invention is characterized in that the protrusion can be variously shaped in the dimple of the golf ball.

Third, the dimple structure for golf balls according to the present invention is characterized in that the height of the protrusion having various shapes is the same as or less than the depth of the dimple so that the protrusion does not protrude outside the dimple.

Fourth, the dimple structure for golf balls according to the present invention is characterized in that the protrusion may be provided in each dimple of the golf ball or, alternatively, may be evenly provided in 15% to 85% of the dimples such that the center of gravity of the golf ball exists at the same point in the golf ball regardless of the orientation of the golf ball.

Fifth, the dimple structure for golf balls according to the present invention is characterized in that the protrusion has a size of 5% to 60% of the cross-sectional area of the dimple.

The present invention, which has been disclosed, is not limited to the above-mentioned embodiments or accompanied drawings, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

MODE FOR THE INVENTION

The above-mentioned objects, features and advantages of the present invention will be further clarified by the following detailed description with reference to the attached drawings. Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

First, fundamental features of the present invention applied to the embodiments will be explained herein below.

FIG. 4 is a sectional view of a golf ball provided with a plurality of dimples each having therein a protrusion according to the present invention. FIG. 5 is a sectional view showing a protrusion provided in a relatively wide dimple of a golf ball, according to the present invention. FIG. 6 is a sectional view showing a protrusion provided in a relatively small dimple of a golf ball, according to the present invention.

A plurality of dimples, which can be variously shaped (this was explained in detail in the above-mentioned embodiments), is evenly disposed on a golf ball. Each dimple can be also provided in various sizes and depths.

The purpose of the dimple structure for golf balls according to the present invention is achieved by integrally providing the protrusions in the dimples having various shapes, sizes, and depths.

The detailed explanation of this is as follows.

As shown in FIG. 4, an outer circumferential line (a), which defines the shape and outer diameter of a golf ball 1, can be defined along an outer circumference of the golf ball 1. Furthermore, an inner circumferential line (b), which is spaced apart from the outer circumferential line (a) by a predetermined distance (D) and connects bottoms of the dimples, can be defined in the golf ball 1. Here, the predetermined distance (D) between the outer circumferential line (a) and the inner circumferential line (b) defines the depth of each dimple.

The special feature of the present invention is that at least one protrusion (in the drawing, one protrusion is shown) is integrally provided in the dimple between the outer circumferential line (a) and the inner circumferential line (b).

As shown in FIG. 5, in the case of existing golf balls, an outer diameter (d) of a dimple which is defined along an outer circumferential line (a) of a golf ball is greater than a depth (D) of the dimple. A bottom diameter (c) of the dimple which is defined along an inner circumferential line (b) of the golf ball is also greater than the depth (D) of the dimple. Therefore, as the outer diameter (d) of the dimple increases, the bottom diameter (c) of the dimple increases along with the outer diameter (d), but on the other hand, the depth (D) of the dimple decreases. Therefore, if the outer diameter (d) of the dimple is relatively large, it may seem that the bottom of the dimple protrudes slightly from a concave surface of the dimple.

In the present invention, even though a dimple has such structure, at least one protrusion can be integrally provided on the bottom of the dimple such that the protrusion is provided between the outer circumferential line (a) of the golf ball and the inner circumferential line (b) in the same manner as that described for the golf ball of FIG. 4.

As shown in FIG. 6, if an outer diameter (d) of a dimple which is defined along an outer circumferential line (a) of a golf ball is short in contrast with the case of the FIG. 5, a bottom diameter (c) of the dimple which is defined along an inner circumferential line (b) of the golf ball also becomes short. Thus, the bottom diameter (c) of the dimple is shorter than the depth (D) of the dimple.

Even in such a structure of the dimple for the golf ball, the present invention is characterized in that at least one protrusion is integrally provided in the dimple between the outer circumferential line (a) of the golf ball and the inner circumferential line (b).

In other words, the dimple structure for golf balls according to the present invention is characterized by at least one protrusion which is integrally provided in the dimple between the outer circumferential line (a) and the inner circumferential line (b) regardless of the shape, size or depth of the dimple.

In the meantime, as shown in FIG. 7, as an outer diameter (d) of a dimple which is defined along an outer circumferential line (a) of a golf ball is reduced, a bottom diameter (c) of the dimple which is defined along the inner circumferential line (b) of the golf ball is also reduced. Then, a protrusion may not be formed on the center portion of the bottom of the dimple. In this case, a bottom diameter (e) of the protrusion may be larger than the bottom diameter (c) of the dimple.

The protrusion of the present invention can be formed in various shapes. This is represented in FIGS. 8 through 12.

FIGS. 8 through 12 are sectional views showing various shapes of protrusions forming a dimple structure for golf balls, according to the present invention. In detail, FIG. 8 shows a cross-section of an elliptical protrusion. FIG. 9 shows a cross-section of a pyramidal protrusion. FIG. 10 shows a cross-section of protrusion having a square-pillar or cylindrical shape. FIG. 11 shows a cross-section of a polygonal protrusion. FIG. 12 shows a cross-section of one or more protrusions.

The protrusion of the present invention may have various other shapes as well as the shapes shown above. 

1. A dimple structure for golf balls, comprising: at least one protrusion integrally provided in a dimple of a golf ball.
 2. The dimple structure for golf balls according to claim 1, wherein the protrusion is provided between an outer circumferential line and an inner circumferential line between which a depth of the dimple is defined, so that the protrusion does not protrude outside the outer circumferential line.
 3. The dimple structure for golf balls according to claim 1, wherein the protrusion is provided in each of a plurality of dimples of the golf ball.
 4. The dimple structure for golf balls according to claim 1, wherein the protrusion is evenly provided in 15% to 85% of a plurality of dimples of the golf ball such that a center of gravity of the golf ball exists at a same point in the golf ball regardless of an orientation of the golf ball.
 5. The dimple structure for golf balls according to claim 1, wherein the protrusion has a size of 5% to 60% of a surface area of the dimple. 